Image display control system and method allowing connection of various kinds of image displays to one supply source

ABSTRACT

This invention discloses an arrangement allowing connection of various kinds of image displays to one supply source in an image display control system having a supply source for transmitting a signal including at least a video signal, and an image display for receiving the signal and displaying a corresponding image. The supply source acquires characteristic data of the image display when it is powered on, determines a signal communication specification with the image display based on the acquired characteristic data, and communicates a signal including the video signal with the determined communication specification. The image display transmits characteristic data for specifying the characteristics of the image display to the supply source, and communicates the signal including the video signal in accordance with the determined communication specification. This invention also discloses an arrangement permitting changing the specifications and version of the control program of the image display.

FIELD OF THE INVENTION

The present invention relates to an image display control system havinga supply source for transmitting a signal including at least a videosignal, and an image display for receiving a signal from the supplysource and displaying a corresponding image, and an image display systemcontrol method.

BACKGROUND OF THE INVENTION

FIG. 49 shows an arrangement used to display various images on atelevision receiver for receiving and displaying a conventionaltelevision program. As shown in FIG. 49, the television receiver isconventionally connected to a terrestrial television broadcasting(VHS/UHF) antenna line and satellite broadcasting (BS) antenna line asantenna lines. As cables extending from other display information supplysources, the television receiver is connected to signal cables such as avideo signal line and acoustic signal line from a video cassetterecorder, a video signal line and acoustic signal line from an LD/DVDplayback apparatus, and a signal line from a digital broadcastingreceiver (STB).

In this manner, the conventional television receiver is integrallyconstituted by a display, input signal selector such as a tuner, and thelike. This inevitably makes the main body large in depth, resulting in abulky housing.

The trend in recent years has been to reduce the depth of televisions,and flat type televisions have become available. This flat typetelevision must be made as thin as possible, and must be light inweight. In a television of this type, therefore, an image display and aterminal for supplying display information to the image display haveseparate housings.

In the conventional flat type television of this type and the like, animage display and a terminal form one television receiver. For example,one terminal can be connected to only one kind of image display.

Inconveniently, the television quality or the like can only be adjustedfrom either the terminal or image display.

The image display and terminal, paired to form one television receiver,basically operate independently. As a matter of course, the imagedisplay and terminal may be manufactured at different times, or only oneof them may be exchanged.

The image display and terminal may be manufactured with a large timedifference or undergo minor changes. In this case, the image display andterminal may have different operating specifications. The image displayand terminal used in this situation cannot take full advantage of theadvantages or improvements in each piece of equipment.

Most of image displays and terminals of this type operate under thecontrol of microcomputers, and their versions can be made to coincidewith each other by changing some programs. Conventionally, however,upgrading requires a special operation by a specialist.

This problem also arises when the image display is to be exchanged withone from a different manufacturer, or of a different size, or having adifferent display method.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an image displaycontrol system having a supply source for transmitting a signalincluding at least a video signal, and an image display for receiving asignal from the supply source and displaying a corresponding image, inwhich one supply source can connect to various kinds of image displays.

It is another object of the present invention to provide easy adjustmentof an image display from the supply source connected thereto.

It is still another object of the present invention to allow for easychanges of the specifications and version of the control program of theimage display.

To achieve the above objects, according to the first aspect of thepresent invention, an image display control system comprises a supplysource for transmitting a signal including at least a video signal, andan image display for receiving the signal from the supply source anddisplaying a corresponding image, the supply source includingcharacteristic acquisition means for acquiring characteristic data ofthe image display when the supply source is powered on, determinationmeans for determining a signal communication specification with theimage display on the basis of the characteristic data acquired by thecharacteristic acquisition means, and communication means forcommunicating a signal including the video signal with the communicationspecification determined by the determination means, and the imagedisplay including characteristic transmission means for transmittingcharacteristic data for specifying a characteristic of the image displayto the supply source, and display communication means for communicatingthe signal including the video signal determined by the determinationmeans of the supply source.

In this case, the characteristic acquisition means comprises, forexample, characteristic request means for transmitting a characteristicdata transmission request to the image display, detection means fordetecting a connection request including characteristic data from theimage display, and characteristic detection means for detecting thecharacteristic data sent back from the image display, and the imagedisplay comprises connection request transmission means for transmittinga connection request including characteristic data of the image displayto the supply source, and characteristic transmission means fortransmitting characteristic data of the image display in correspondencewith a characteristic data transmission request from the supply source.

The characteristic request means preferably stops transmitting thecharacteristic data transmission request when no characteristic data issent back from the image display even upon transmitting thecharacteristic data transmission request a predetermined number of timesafter the supply source is powered on. Alternatively, the connectionrequest transmission means monitors detection of the characteristic datatransmission request from the supply source when no characteristic datatransmission request is sent back from the supply source even upontransmitting the connection request a predetermined number of timesafter the image display is powered on.

It is more preferable that the characteristic data transmission requestfrom the characteristic request means include a specificationinformation transmission request of the image display, and the imagedisplay send back specification information of the image display incorrespondence with the specification information transmission request.

The characteristic data transmission request from the characteristicrequest means includes an adjustment information transmission request ofthe image display, and the image display sends back adjustmentinformation of the image display in correspondence with the adjustmentinformation transmission request. Alternatively, the determination meanspreferably specifies a display screen size of the image display from thecharacteristic data, obtains a video signal amount to be transmitted incorrespondence with the specified display screen size, and determines asignal communication specification.

The signal communication specification determined by the determinationmeans preferably includes a vertical synchronization period, ahorizontal synchronization period, and a video signal transmission clockperiod for transmitting a video signal.

The characteristic data of the image display preferably includes atleast any one of

-   -   the number of pixels and pixel layout of a display device of the        image display,    -   an emission characteristic of the display device of the image        display,    -   a gray level characteristic of the image display (the number of        gray levels and a gamma characteristic of the display device),    -   the type of image display (a screen size, an aspect ratio, and        the type of device),    -   a specification of an audio playback system of the image        display, and    -   a displayable frame frequency of the image display.

With this arrangement, the supply source can transmit a video signal inaccordance with the characteristics of a connected image display. Hence,the supply source can easily transmit a video signal in accordance witheven changed characteristics of the connected image display.

At the start of operation, the supply source can reliably recognize theadjustment state of the image display. Any error caused by a shift inadjustment result can be prevented prior to operation.

To achieve the above objects, according to the second aspect of thepresent invention, an image display control system comprises a terminalfor transmitting a signal including at least a pair of video andacoustic signals, and an image display for receiving the signal from theterminal and displaying a corresponding image, the terminal includingrequest means for detecting a program specification held in the imagedisplay upon powering on the terminal, and when program download isdetermined to be necessary from the detected program specification,requesting program download of the image display, and program downloadmeans for downloading a program, and the image display including programupdate means for storing, in a corresponding program memory of the imagedisplay, the downloaded program transmitted subsequently upon receptionof the program download request.

In this case, the request means preferably acquires a program ID storedin the program memory of the image display, and detects a programspecification.

When the request means determines that program download is unnecessaryand upon completion of program download, the terminal preferablyperforms display control for the image display.

With this arrangement, a program specification concerning displaycontrol of the image display can be updated prior to display control,and a desired display quality can be easily obtained. The processingversion of the image display can also be upgraded.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram for explaining the basic arrangement accordingto the first embodiment of the present invention;

FIG. 2 is a block diagram showing the detailed arrangements of an imagedisplay and terminal in the first embodiment;

FIG. 3 is a block diagram showing the detailed arrangements of aninterface circuit portion and modem input/output portion between theterminal and image display in the first embodiment;

FIG. 4 is a block diagram showing a detailed arrangement of a portion ofthe input I/F of the first embodiment in which pieces of imageinformation of different specifications are received and output to avideo signal processor;

FIGS. 5A and 5B are timing charts showing output timing of the input I/Fwhen an NTSC image signal is input to the input I/F in the firstembodiment shown in FIG. 4;

FIGS. 6A and 6B are timing charts showing output timing of the input I/Fwhen an HDTV image signal is input to the input I/F in the firstembodiment shown in FIG. 4;

FIG. 7 is a view showing an operation confirmation control sequence withthe image display after the terminal is powered on in the firstembodiment;

FIG. 8 is a flow chart showing control upon power-on operation of theterminal in the first embodiment;

FIG. 9 is a flow chart showing control upon power-on operation of theimage display in the first embodiment;

FIG. 10 is a view showing a structure of a communication packet used incommunication control upon power-on operation in the first embodiment;

FIG. 11 is a view showing another structure of the communication packetused in communication control upon power-on operation in the firstembodiment;

FIG. 12 is a view showing a data structure in a unit period in the firstembodiment;

FIG. 13 is a view showing a packet structure in transmitting/receiving acommand packet in the first embodiment;

FIGS. 14A and 14B are views each showing an adjustment data format inthe first embodiment;

FIG. 15 is a flow chart showing operation mode setup processing of theterminal in the first embodiment;

FIG. 16 is a flow chart showing operation mode setup processing of theimage display in the first embodiment;

FIG. 17 is a timing chart showing data communication control timing in avertical synchronization signal generation period in the image displayand terminal of the first embodiment;

FIG. 18 is a timing chart showing data communication control timing in ahorizontal synchronization signal generation period in the image displayand terminal of the first embodiment;

FIG. 19 is a timing chart for explaining data communication timingbetween the image display and terminal when a display panel has 852dots×480 dots in the first embodiment;

FIG. 20 is a timing chart for explaining data communication timingbetween the image display and terminal when the display panel has 640dots×480 dots in the first embodiment;

FIG. 21 is a timing chart for explaining data communication timingbetween the image display and terminal when the display panel has 1,365dots×768 dots in the first embodiment;

FIG. 22 is a timing chart for explaining data communication timingbetween the image display and terminal when the display panel has 1,365dots×768 dots, and the frequency of a horizontal transfer clock (CLK) ischanged in the first embodiment;

FIG. 23 is a timing chart showing communication timing between theterminal and image display when audio data is communicated at once everyVSYNC timing in the first embodiment;

FIG. 24 is a timing chart showing communication timing between theterminal and image display when command data is communicateddivisionally at respective HSYNC timing in the first embodiment;

FIG. 25 is a timing chart showing communication timing between theterminal and image display when command data is controlled to becommunicable over the period except for a video data enable period andaudio data communication period in the first embodiment;

FIG. 26 is a block diagram for explaining a basic system arrangement ofthe second embodiment according to the present invention;

FIG. 27 is a block diagram for explaining another basic systemarrangement of the second embodiment according to the present invention;

FIG. 28 is a block diagram showing the detailed arrangement of thesecond embodiment;

FIG. 29 is a block diagram showing the arrangement of the thirdembodiment according to the present invention;

FIG. 30 is a timing chart for explaining information communicationtiming in the third embodiment;

FIG. 31 is a block diagram showing the arrangement of the fourthembodiment according to the present invention;

FIG. 32 is a timing chart for explaining communication control duringthe VSYNC period between the terminal and image display of the fourthembodiment;

FIG. 33 is a timing chart for explaining communication control duringthe HSYNC period between the terminal and image display of the fourthembodiment;

FIG. 34 is a block diagram showing the arrangement of the fifthembodiment according to the present invention;

FIG. 35 is a view for explaining a packet structure used in the fifthembodiment;

FIG. 36 is a view for explaining the detailed structure of an addresscommand shown in FIG. 35;

FIG. 37 is a block diagram showing a state in which a plurality of imagedisplays are connected in the fifth embodiment;

FIG. 38 is a flow chart for explaining command data reception processingof the image display in the fifth embodiment;

FIG. 39 is a block diagram showing the arrangement of the sixthembodiment according to the present invention;

FIG. 40 is a flow chart showing download processing of the terminal inthe sixth embodiment;

FIG. 41 is a flow chart showing download processing of the image displayin the sixth embodiment;

FIG. 42 is a block diagram showing the arrangement of the seventhembodiment according to the present invention;

FIG. 43 is a view showing the layout of respective units in the seventhembodiment;

FIG. 44 is a flow chart showing control of the image display upondetecting an environmental change in the seventh embodiment;

FIG. 45 is a flow chart showing control of the terminal upon detectingan environmental change in the seventh embodiment;

FIG. 46 is a block diagram for explaining an example in which part of aninterface cable adopts radio communication in the eighth embodiment ofthe present invention;

FIG. 47 is a block diagram for explaining an arrangement of the ninthembodiment according to the present invention;

FIG. 48 is a timing chart for explaining communication control duringthe HSYNC period between the terminal and image display of the 10thembodiment of the present invention; and

FIG. 49 is a block diagram showing an arrangement used to displayvarious images on a television receiver for receiving and displaying aconventional television program.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

First Embodiment

FIG. 1 is a view for explaining the basic arrangement according to thefirst embodiment of the present invention. In FIG. 1, reference numeral1 denotes an image display which has a wall-mounted thin structure inthis embodiment; and reference numeral 2, a terminal which outputsdisplay data and acoustic data to the image display 1 in accordance withsynchronous bidirectional serial data (to be described later), andincludes a tuner for receiving a television program, as will bedescribed later.

Reference numeral 3 denotes a video cassette recorder serving as asupply source of an image and acoustic signal to the terminal 2;reference numeral 4, an LD/DVD player for playing back a laser disk orDVD disk; and reference numeral 5, an STB for receiving and selecting adigital program.

The terminal 2 is connected to connection cables extending from thesupply sources for the respective image signals and the like, and to aterrestrial television broadcasting (VHS/UHS) antenna line and satellitebroadcasting (BS) antenna line extending to the tuner. As thecommunication medium between the terminal 2 and image display 1, onlyone thin cable is basically connected. Even in the wall-mounted imagedisplay, the cable layout is simplified and does not impair appearance.

The specific arrangements of the image display 1 and terminal 2according to the first embodiment in the above system arrangement willbe explained with reference to FIG. 2. The specific arrangement of theimage display 1 will be first described.

In the image display 1, reference numeral 101 denotes a display CPUwhich controls the whole image display 1, and incorporates a ROM storinga control sequence and the like shown in a flow chart (to be describedlater). The display CPU 101 executes reception control of variousreception data in accordance with command data received by the terminal2 via a display modem 103. The display CPU 101 controls each unit via acontrol bus 151.

Reference numeral 102 denotes a connection cable receiving connector tothe terminal 2. The image display 1 also includes the display modem 103.Reference numeral 104 denotes a timing generator for generating thecontrol timing of the image display 1 under the control of the displayCPU 101 in accordance with a regenerated SYNC signal or CLK signal fromthe display modem 103.

Reference numeral 105 denotes a video signal processor for converting a24-bit digital video signal decoded by the display modem 103 into aluminance image signal which can be displayed on a display panel 110.Reference numeral 106 denotes a panel driver for driving the displaypanel 110 with a luminance signal from the video signal processor 105 attiming from the timing generator in accordance with driving conditionsfrom the display CPU 101. The image display 1 comprises the displaypanel 110.

Reference numeral 121 denotes a D/A converter for receiving a 16-bitdigital audio signal from the display modem 103 at the reception timingfrom the timing generator and converting the received signal into acorresponding analog audio signal. Reference numeral 122 denotes anaudio amplifier for amplifying an input analog signal from the D/Aconverter 121, and reference numeral 123 denotes a speaker.

Reference numeral 130 denotes a user interface (user I/F) for inputtingvarious operations from the user. These operations include, e.g.,display adjustment and detection of a remote controller input.

Next, details of the terminal 2 will be described.

In the terminal 2, reference numeral 201 denotes a terminal CPU whichcontrols the whole terminal 2, and includes a ROM storing a controlsequence and the like shown in a flow chart (to be described later). Theterminal CPU 201 controls a timing generator 204 and video signalprocessor 205 so as to transmit display data with a desired format via aterminal modem 203. The terminal CPU 201 similarly outputs controlcommand data to the image display 1 via the terminal modem 203. Theterminal CPU 201 controls each unit via a control bus 251.

Reference numeral 202 denotes a cable connector to the image display 1.The terminal 2 comprises the terminal modem 203, and terminal timinggenerator 204 for outputting a SYNC signal or CLK signal, a commandtiming signal representing command transmission timing, and the likecontrolling the terminal CPU 201 and to the terminal modem 203.

The video signal processor 205 receives an input image signal from aninput I/F 220 and an image signal (video signal) from a tuner 240,converts a received signal into a corresponding 24-bit digital videosignal, and outputs the digital video signal to the terminal modem 203.Reference numeral 210 denotes an audio signal processor for similarlyreceiving an input acoustic signal (audio signal or the like) from theinput I/F 220, converting the received signal into a corresponding16-bit digital acoustic signal, and outputting the digital acousticsignal to the terminal modem 203.

The input I/F 220 interfaces the supply sources (3 to 5) for respectivepieces of image information and the like shown in FIG. 1. Further, theinput I/F 220 receives an image information signal and acoustic signalfrom the tuner 240, identifies either input under the control of theterminal CPU 201, and outputs an acoustic signal to the audio signalprocessor 210, an image information signal as a video signal to thevideo signal processor 205, a clock signal such as a SYNC signal to thetiming generator 204, and input signal determination data to theterminal CPU 201.

Reference numeral 230 denotes a user interface (user I/F) for inputtingvarious operations from the user. These operations include, e.g.,display adjustment and detection of a remote controller input. The tuner240 receives terrestrial television program signals and satelliteprogram signals. Reference numerals 221 to 223 denote input terminalsextending from the supply sources (3 to 5). Reference numeral 241denotes a terrestrial television broadcasting antenna input; andreference numeral 242, a satellite broadcasting antenna input.

The terminal 2 having this arrangement is not limited by thespecifications of a connected image display, and allows connecting imagedisplays of various specifications so long as they have similarinterface specifications.

The specific arrangements of the interface circuit portion and modeminput/output portion between the terminal 2 and image display 1 will beexplained with reference to FIG. 3.

In the display modem 103, reference numeral 310 denotes an input/outputdriver circuit for receiving a signal through a cable in accordance witha communication direction control signal from the timing generator 104and outputting a signal from a modulator 312. Reference numeral 311denotes a demodulator for demodulating a reception signal from thereceiver of the input/output driver circuit 310, converting thedemodulated serial demodulation data into 24-bit demodulated paralleldata, and outputting the demodulated parallel data. The modulator 312converts 16-bit parallel control data from the display CPU 101 intoserial data, modulates the serial data, and outputs the modulated datato the driver of the input/output driver circuit 310.

Reference numeral 313 denotes a demultiplexer for demultiplexing ademodulated signal in response to a timing control signal from thetiming generator 104 and distributing the demultiplexed signal to eachunit. The demultiplexer 313 outputs a regenerated SYNC signal and CLKsignal to the timing generator 104, outputs a demultiplexed video signalto the video signal processor 105, outputs a demultiplexed acousticsignal to the D/A converter 121, and outputs demultiplexed commandinformation to the display CPU 101. Reference numeral 314 denotes adriver circuit for outputting control data from the display CPU to themodulator 312.

In the terminal modem 203, reference numeral 320 denotes an input/outputdriver circuit for receiving a signal through a cable in accordance witha communication direction control signal from the timing generator 204and outputting a signal from a modulator 322. Reference numeral 321denotes a demodulator for demodulating a reception signal from thereceiver of the input/output driver circuit 320, converting thedemodulated serial demodulation data into 16-bit demodulated paralleldata, and outputting the demodulated parallel data to the terminal CPU201 via a driver circuit 324. The modulator 322 converts a 24-bitparallel multiplexed signal from a multiplexer 323 into serial data,modulates the serial data, and outputs the modulated data to the driverof the input/output driver circuit 320.

The multiplexer 323 receives a video signal from the video signalprocessor 205, an acoustic signal from the audio signal processor 210,and control information from the terminal CPU 201, multiplexes thesesignal and information in response to a timing signal from the timinggenerator 204 so as to prevent these signal and information fromoverlapping each other, and outputs the multiplexed signal to themodulator 322. The driver circuit 324 outputs control data from theimage display 1 via the demodulator 321 to the terminal CPU 201.

In the first embodiment, the terminal 2 and image display 1 are adaptedto exchange various kinds of information via only a pair of signallines, and hence the connection cable can be simplified and thinned.Basically, the connection cable connecting the image display 1 andterminal 2 is a twisted pair cable. The transmission format isdetermined by the specifications of the image display 1 (to be describedlater) and the type of input signal received by the terminal 2.

However, the communication medium connecting the two image display andterminal is not limited to an electric conductor cable, but may be anoptical signal communication line such as an optical fiber or wirelesscommunication such as electromagnetic waves. For example, as shown inFIG. 46 (to be described later), the communication medium may employ anoptical communication unit attached to the upper or lower portion of thedisplay, and a terminal-side optical communication unit installed nearthe optical communication unit of the display that is connected to theterminal via an electric wire or the like.

The input I/F 220 of the first embodiment is adapted to input pieces ofimage information of various specifications. FIG. 4 shows an arrangementof a portion of the input I/F 220 of this embodiment in which the piecesof image information of different specifications are received and outputto the video signal processor 205. Although FIG. 4 shows only an imagesignal, the input I/F 220 also receives, as for an acoustic signal,signals of different specifications, converts them into commonspecifications, and outputs the converted signals.

The image information input portion of the input I/F 220 is adapted toinput a composite input and S terminal input of NTSC specifications, aMuse signal input and component signal input of HDTV specifications, anda PC input of PC (computer graphics) specifications. The input I/F 220converts signals of these specifications into R, G, and B signals, andoutputs the R, G, and B signals to the video signal processor 205.

For example, an NTSC composite signal is sent via the composite input toan NTSC decoder 401 where the signal is decoded and output to a selector402. The selector 402 also receives an S input signal via the S terminalinput, and selects either input. In this case, the selector 402 ispreferably controlled to give priority to the S terminal input.

A signal from the selector 402 is sent to an IP converter 404 and syncseparator 403. The IP converter (Interlaced/Progressive converter) 404receives a video signal. If progressive scanning is requested inaccordance with the specifications of the image display 1, the IPconverter 404 outputs, e.g., Y signal/color difference signals acquiredby converting a video signal of 240 lines/60 Hz into a signal of 480lines/60 Hz. If the image display 1 comprises a panel with the number ofpixels (320×240) corresponding to QVGA, the IP converter 404 does notexecute any IP conversion, and directly outputs a video signal of 240lines/60 Hz.

A matrix processor 405 converts the signal from the IP converter 404into corresponding R, G, and B signals, and outputs them to amultiplexer 440. On the other hand, the sync separator 403 separatessynchronization signals (H-SYNC signal and V-SYNC signal), and outputsthem to an input signal determination unit 430.

For example, a HDTV Muse signal is decoded by a Muse decoder 411 andoutput to a selector 412. In the first embodiment, high-vision componentsignals are also input, and directly input to the selector 412 whichselects either input. In this case, the selector 412 is controlled togive priority to the component inputs.

The Y signal/color difference signals from the selector 412 are sent toa matrix processor 415. The matrix processor 415 converts these signalsinto corresponding R, G, and B signals, and outputs them to themultiplexer 440. On the other hand, a sync separator 413 separatessynchronization signals (H-SYNC signal and V-SYNC signal), and outputsthem to the input signal determination unit 430. Moreover, for example,a PC input signal of PC specifications is received by an input buffer421, a synchronization signal is sent to the input signal determinationunit 430, and R, G, and B signals are output to the multiplexer 440.

The input signal determination unit 430 receives each synchronizationsignal (SYNC signal), determines an input signal on the basis of thefrequency and type (polarity, H/V-separated or mixed SYNC, and the like)of received synchronization signal, and informs the terminal CPU 201 ofthe determination results. The multiplexer 440 selects one of the inputsignals under the control of the terminal CPU 201, and outputs theselected signal to the video signal processor 205.

FIGS. 5A and 5B show output timing of the input I/F 220 when an NTSCimage signal is input to the input I/F 220 shown in FIG. 4.

The example shown in FIGS. 5A and 5B show timing when as an output fromthe input I/F 220, a signal having an effective video period of about480 lines for the vertical period and about 28.6 μS for the horizontalperiod is displayed by over-scanning of about 10%. The display period isabout 430 lines for the vertical period, and about 25.7 μS for thehorizontal period. In the first embodiment, the default settings of 10%over-scanning and the like can be changed via the user I/F 230.

In NTSC specifications, as shown in FIGS. 5A and 5B, an NTSC imagesignal is input such that a vertical synchronization signal (VSYNCsignal) arrives at a period of 1/59.94 Hz and is converted by the IPconverter at a double speed, and a horizontal synchronization signal(HSYNC signal) arrives at a period of 1/31.47 kHz.

Then, for example, the period shown in FIGS. 5A and 5B is received bythe video signal processor 205 and sampled again so as to match theresolution of the image display 1. When the display panel 110 of theimage display has 852×480 pixels, the horizontal synchronization signalis sampled by a CLK signal of about 33.1 MHz, and the verticalsynchronization signal undergoes, e.g., inter-line interpolation so asto change image data of about 430 lines into image data of about 480lines.

FIGS. 6A and 6B show output timing of the input I/F 220 upon receptionof an HDTV input which is also a television image. The example in FIGS.6A and 6B show timing when an output from the input I/F 220 is displayedby over-scanning of about 7%.

As shown in FIGS. 6A and 6B, an HDTV image signal is input such that avertical synchronization signal (VSYNC signal) arrives at a period of1/60 Hz, and a horizontal synchronization signal (HSYNC signal) arrivesat a period of 1/33.75 kHz. Then, for example, the period shown in FIGS.6A and 6B is received by the video signal processor 205 and sampledagain so as to match the resolution of the image display 1. When thedisplay panel 110 of the image display has 852×480 pixels, thehorizontal synchronization signal is sampled by a CLK signal of about35.5 MHz, and about 480 lines of the vertical synchronization signalamong 517 effective lines are directly output.

The control of the first embodiment having the above arrangement will bedescribed. The terminal 2 of this embodiment is adapted to control imagedisplays of various specifications, as described above. For this reason,when the terminal 2 is powered on, power-on processing to confirm thespecifications of a connected image display is first executed.

An operation confirmation control sequence with the image display 1after the terminal 2 is powered on will be explained with reference toFIG. 7. According to this operation confirmation control sequence, thespecifications of a connected image display are unknown, so that anasynchronous communication control sequence using a communication rateof 300 BPS or 1,200 BPS is determined as a communication controlsequence capable of most easily performing communication control with apartner. Using this communication control sequence, communicationcontrol is executed.

Upon power-on operation, the terminal 2 sends an ID request (connectionrequest) to the image display 1. The image display 1 having receivedthis request immediately sends back the display ID to the terminal 2. Ifthe ID is sent back from the image display 1, the terminal 2 determinesthat the image display 1 has been powered on.

If the image display 1 has not been powered on when the terminal 2 ispowered on, the image display 1 does not send back any response to theID request. When the terminal 2 does not receive any ID from the imagedisplay 1 even upon sending the ID request a predetermined number oftimes, e.g., n times at a predetermined interval, the terminal 2determines that the image display 1 has not been powered on yet, andstops access to the image display 1.

When the apparatus of the image display 1 is powered on, the imagedisplay 1 monitors a command such as an ID request sent from theterminal 2 during a predetermined period as a standby period. If acommand is sent, the image display 1 performs corresponding control.That is, if an ID request is sent, the image display 1 sends back itsID.

If no connection request or the like is sent from the terminal 2 duringthe standby period, the image display 1 transmits a connection request(display ID is added as a parameter to the connection request command)to the terminal 2 after the standby period, as shown in FIG. 7. Theterminal 2 always monitors reception of a command sent from the imagedisplay 1, and when detecting reception of the connection request,requests the image display 1 to transmit its specifications. Then, theimage display 1 transmits display specification information to theterminal 2.

The terminal 2 requests transmission of necessary adjustment data basedon the specifications. In response to the adjustment data transmissionrequest, the image display 1 transmits the held image display adjustmentdata to the terminal 2.

Since the terminal 2 can obtain the specifications of the image display1 from the received data, the terminal 2 shifts to normal processingconforming to the specifications of the image display 1.

When the image display 1 does not receive any reply from the partnerterminal 2 even upon transmitting a connection request to the terminal 2a predetermined number of times after the apparatus is powered on, theimage display 1 determines that the connected terminal has not beenpowered on yet, and enters a mode in which reception of command datafrom the terminal 2 is monitored. If the terminal 2 is powered on andsends an ID request, the image display 1 shifts to control of sendingback a connection request.

More specifically, the first embodiment establishes communicationbasically using the terminal 2 as a master and the image display 1 as aslave.

In the above description, the terminal 2 stops access after trying toconnect a predetermined number of times, and the image display 1 outputsa connection request. Alternatively, it is also possible that theterminal 2 always periodically accesses the image display 1, and theimage display 1 does not spontaneously transmit any command always as aslave.

Note that the ID is an identification code which specifies the hardwarespecifications of the image display, and represents, e.g., themanufacturer and model. The specifications represent the hardwarespecifications of the image display 1, and include, e.g., the number ofpixels of the display panel, pixel layout, color/monochrome, devicetype, screen size, aspect ratio, the number of gray levels, gammacharacteristics, displayable frame frequency, and audio specification.The specifications further include items adjustable on the imagedisplay.

Adjustment data includes, e.g., contrast, color balance, brightness,black level, display position, display size, volume, and balance, andcan be changed even during normal operation. Adjustment information isexchanged between the image display 1 and terminal 2. Adjustment dataalso includes information about an adjustment authorization which allowseither of the terminal 2 and image display 1 to adjust items adjustableby them.

As will be described later, the terminal 2 stores in a nonvolatilememory (not shown) a pair of ID and specifications of the image display1 having already been connected. When an ID from the image display 1coincides with the previous ID, the terminal 2 has already held thespecifications and the like of the image display 1, and henceimmediately shift to normal processing without requesting anytransmission.

In the image display 1, data before power-off operation is stored in theinternal nonvolatile memory (not shown) of the display CPU 101 in theimage display, and read out and displayed upon power-on operation.Alternatively, readout adjustment data is transmitted from the imagedisplay 1 to the terminal 2, and adjustment processing is done in theterminal 2 and image display 1 in accordance with the above-describedadjustment authorization.

Detailed control upon power-on operation will be explained withreference to FIGS. 8 and 9. FIG. 8 is a flow chart showing control uponpower-on operation of the terminal 2 in the first embodiment, and FIG. 9is a flow chart showing control upon power-on operation of the imagedisplay 1 in the first embodiment.

The control of the terminal 2 will be described with reference to FIG.8. When the terminal 2 is powered on, executes a power-on controlsequence shown in FIG. 8 in accordance with a predeterminedcommunication control sequence.

In step S1 of FIG. 8, the terminal 2 transmits an ID request (connectionrequest) command to the connected image display 1. In step S2, theterminal 2 checks whether it receives an ID from the image display 1. IfNO in step S2, the terminal 2 shifts to step S3 to check whether apredetermined time has elapsed. If NO in step S3, the terminal 2 returnsto step S2 to monitor reception of an ID within the predetermined time.If no ID is sent from the image display 1 even upon the lapse of thepredetermined time, the terminal 2 advances to step S4 to check whetherto have transmitted an ID request command to the image display 1 apredetermined number of times, e.g., n times. If NO in step S4, theterminal 2 returns to step S1 to transmit an ID request command again.

If YES in step S4, the terminal 2 returns to step S2 to monitortransmission of an ID (connection request) from the image display 1. Ifthe terminal 2 receives the ID from the image display 1, the terminal 2proceeds from step S2 to step S5, and checks whether the received ID isan ID which has already been held in the terminal 2, and can be used tograsp the specifications of the connected image display.

If NO in step S5, the terminal 2 advances from step S5 to step S6, andchecks whether a default switch representing a standard monitorrecommended as a standard image display of the terminal 2 is ON (whetherthe standard monitor is connected). If NO in step S6, the terminal 2advances to step S7 to transmit a specification request command to theimage display 1. In step S8, the terminal 2 checks whetherspecifications from the image display 1 have been received. If NO instep S8, the terminal 2 shifts to step S9 to check whether apredetermined time has elapsed. If NO in step S9, the terminal 2 returnsto step S8 to monitor reception of specifications within thepredetermined time. If no specifications are sent from the image display1 even upon the lapse of the predetermined time, the terminal 2 advancesto step S10 to check whether it cannot receive any specifications withinthe predetermined time upon transmitting a request a predeterminednumber of times. If NO in step S10, the terminal 2 returns to step S7 totransmit a specification request command again.

If YES in step S10, the terminal 2 determines that the image display 1has been powered off or disabled, and returns to step S1 to shift totransmission processing of an ID request command to the image display 1.

If YES in step S8, the terminal 2 advances to step S11 to check whetherthe received specifications are ones applicable to the terminal 2. IfYES in step S1, the terminal 2 shifts to step S15.

If NO in step S1, the terminal 2 shifts to step S12 to selectspecifications considered to be able to most satisfy the receivedspecifications, from specifications applicable to the terminal 2. Instep S13, the terminal 2 displays the selected specification informationtogether with an error display. Then, the terminal 2 shifts to step S15.

If YES in step S5 or S6, the terminal 2 advances to step S14 to selectheld specifications, and shifts to step S15.

In step S15, the terminal 2 stores the selected specifications of theimage display 1 in a nonvolatile memory (not shown), and shifts to stepS16. In step S16, the terminal 2 requests the image display 1 totransmit necessary adjustment data on the basis of the selectedspecifications. In step S17, the terminal 2 checks whether adjustmentdata from the image display 1 has been received. If NO in step S17, theterminal 2 shifts to step S18 to check whether a predetermined periodhas elapsed. If NO in step S18, the terminal 2 returns to step S17 tomonitor reception of adjustment data within the predetermined time. Ifno adjustment data is sent from the image display 1 even upon the lapseof the predetermined time, the terminal 2 advances to step S19 to checkwhether it cannot receive any adjustment data within the predeterminedtime upon transmitting a request a predetermined number of times. If NOin step S19, the terminal 2 returns to step S16 to transmit anadjustment data request command again.

If YES in step S19, the terminal 2 determines that the image display 1has been powered off or disabled, and returns to step S1 to shift totransmission processing of an ID request command to the image display 1.

If the terminal 2 receives adjustment data in step S17, the terminal 2can grasp the specifications of the image display 1 from the adjustmentdata, and thus shifts to normal communication processing conforming tothe specifications of the image display 1 in FIG. 7.

The control of the image display 1 will be described. When the imagedisplay 1 is powered on, it executes a power-on control sequence(command reception control sequence) shown in FIG. 9, in accordance witha predetermined communication control sequence.

In step S31 of FIG. 9, the image display 1 resets a timer for counting acommunication response time. In step S32, the image display 1 checkswhether a command has been received. If NO in step S32, the imagedisplay 1 shifts to step S33 to check whether a predetermined time haselapsed. If NO in step S33, the image display 1 returns to step S32 tomonitor reception of a command within the predetermined time. If theimage display 1 does not receive any command from the terminal 2 evenupon the lapse of the predetermined time, the image display 1 shifts tostep S34 to transmit a connection request including the display ID tothe terminal 2. Then, the image display 1 returns to step S31.

If YES in step S32, the image display 1 advances to step S35 to analyzethe received command. In step S36, the image display 1 determineswhether the analyzed command is an ID request command. If YES in stepS36, the image display 1 advances to step S37 to send back the displayID to the terminal 2, and returns to step S31.

If NO in step S36, the image display 1 shifts to step S38 to determinewhether the received command is a specification request command. If YESin step S38, the image display 1 shifts to step S39 to send back displayspecification information to the terminal 2, and returns to step S31.

If NO in step S38, the image display 1 advances to step S40 to determinewhether the received command is an adjustment data request command. IfYES in step S40, the image display 1 advances to step S41 to send backdisplay adjustment data to the terminal 2, and returns to step S31.

If NO in step S40, the image display 1 advances to step S42 to determinewhether the received command is idle communication (ENQ). If NO in stepS42, the image display 1 determines that the received command is aninvalid one which cannot be executed, and shifts to step S43. Then, theimage display 1 sends back NAK (signal representing that the receivedcommand is an invalid one) to the terminal 2, and returns to step S31.

If YES in step S42, the image display 1 shifts to step S44 to send back“ENQ”, and shifts to normal communication processing.

A structure of a communication packet used in transmitting/receivingcommand data and the like in the above communication control will bedescribed with reference to FIG. 10. FIG. 10 is a view showing astructure of a communication packet used in communication control uponpower-on operation in the first embodiment.

In this embodiment, the specifications of a partner apparatus have notbeen determined, so bit synchronization in communication cannot beestablished. For this reason, it is desirable to perform asynchronous(start-stop synchronous) communication which enables reception by addinga start bit and stop bit to the head and end of transmission/receptiondata and establishing synchronization every data transmission/reception.

As a communication control sequence, e.g., an ISO 1745 sequence can beadopted. This sequence is made up of an SOH 501 representing the startof the heading of an information message, a command code 502 and datacount 503 constituting the heading, an STX 504 representing the start ofthe text and the end of the heading, a predetermined number of text datagroups 505 each made up of a pair of item number and corresponding data,an ETX 506 representing the end of the text, and a check sum (BCC) 507for checking whether text data has been transmitted without any error.

The command code 502 includes an ID request command, ID transmissioncommand, specification request command, specification transmissioncommand, adjustment data request command, adjustment data transmissioncommand, channel selection command, and the like. When a video printeris connected (to be described later), the command code 502 includes avideo print command and the like.

This packet structure can be used not only in power-on control but alsoin transmission/reception of command data in normal communication. Inthe latter case, when a pair of an item number and corresponding itemdata are transmitted/received as data to be transmitted as text data,only a changed data item among data items is controlled to betransmitted/received, thereby reducing the amount of thetransmission/reception data.

In this case, transmission of changed item data must be controlled to becompleted only after receiving a confirmation packet, e.g., “ACK” packetrepresenting that an updated data item from a partner apparatus hasreliably been received.

In the above description, a data item number and corresponding item dataare transmitted as text data. However, the present invention andembodiments are not limited to this. For example, when the packet is afixed-length packet having a packet length uniquely determined by acommand code, and all the items are to be transmitted though only oneitem was changed, command data may be communicated using a fixed-lengthpacket shown in FIG. 11.

In this case, compared to the packet structure of FIG. 10, the datacount 503 is omitted, and no item number need be transmitted as far asthe item order has been determined. Hence, the packet can be made up ofan SOH 511, command code 512, STX 514, data 515, ETX 516, and check sum(BCC) 517.

Upon the completion of power-on processing, the processing shifts tonormal communication processing. In normal processing, the communicationspeeds of respective devices and the transmission/reception timing ofsynchronization signals (VSYNC and HSYNC) between the devices areuniquely determined, and thus various communication control operationscorresponding to the synchronization signals are done.

The basic data communication format of the first embodiment will beexplained with reference to FIGS. 12 to 14B. FIG. 12 is a view showing adata structure in a unit period in the first embodiment, and FIG. 13 isa view showing a packet structure in transmitting/receiving a commandpacket. The example of FIG. 13 concerns a fixed-length packet. FIGS. 14Aand 14B are views each showing an adjustment data format.

In the first embodiment, image data and acoustic data are communicatedin a unit period shown in FIG. 12. This unit period is the period of thehorizontal synchronization signal (HSYNC) or vertical synchronizationsignal (VSYNC) of a video signal.

The unit period is comprised of a first sync code (H number) 601, nsecond image data (serial) 602, third acoustic data 603, and fourthcommand data (bidirectional control) 604.

The fourth command data 604 has, e.g., a detailed packet structure shownin FIG. 13. The packet is made up of a header 651 representing the typeof command data, data area 652, and check sum 653.

An example of adjustment data is shown in FIG. 14 as a structure of thedata field. FIG. 14A shows an example of adjustment data from the imagedisplay 1 to the terminal 2, and FIG. 14B shows an example of adjustmentdata from the terminal 2 to the image display 1.

Adjustment data from the image display 1 to the terminal 2 includesdisplay type data, a command representing the adjustment mode, a commandrepresenting the adjustment authorization, contrast setting data, colortemperature setting data (G, B, and R), brightness setting data, blacklevel setting data (G, B, and R), gamma adjustment data (G, B, and R),display mode setting data, horizontal/vertical display size settingdata, horizontal/vertical display position setting data, volume settingdata, right & left volume balance setting data, audio specificationsetting data of the display, and the like.

On the other hand, adjustment data from the terminal 2 to the imagedisplay 1 includes reception signal type data, a command representingthe adjustment mode, a command representing the adjustmentauthorization, contrast setting data, color temperature setting data (G,B, and R), brightness setting data, black level setting data (G, B, andR), gamma adjustment data (G, B, and R), display mode setting data,horizontal/vertical display size setting data, horizontal/verticaldisplay position setting data, volume setting data, right & left volumebalance setting data, and the like.

Setup processing first executed in the normal processing operation modeof the first embodiment upon the completion of the above-describedpower-on processing will be described with reference to the flow chartsof FIGS. 15 and 16. FIG. 15 is a flow chart showing operation mode setupprocessing of the terminal 2 in the first embodiment, and FIG. 16 is aflow chart showing operation mode setup processing of the image display1 in the first embodiment.

If the terminal 2 receives specification information, adjustment data,and the like from the connected image display 1 by power-on processingshown in FIG. 8, the terminal 2 shifts to setup processing in theoperation mode shown in FIG. 15. In step S51, the terminal CPU 201determines an input signal based on input signal determination data fromthe input I/F 220. In step S52, the terminal CPU 201 acquires specificdata of the image display 1 based on adjustment data and the like.

In step S53, the terminal CPU 201 determines an image processing modefrom the acquired data, and also specifies an audio processing mode. Forexample, the terminal CPU 201 specifies the image processing mode as anNTSC processing mode, and sets the audio processing mode to a stereomode.

In step S54, the terminal CPU 201 instructs the timing generator 204 togenerate a timing signal at signal processing timing corresponding tothe determined processing mode.

In step S55, the terminal CPU 201 generates communication (transmission)processing timing. For example, the CPU 201 outputs an enable signal andthe like for time-division multiplexing of respective processing data,such as the communication direction control timing to the terminal modem203, interrupt signal generation timing to the terminal CPU 201 forcommand transmission/reception, and command data processing timing forthe video signal processor 205, audio signal processor 210, and terminalCPU 201. The CPU 201 sets to perform communication control shown in FIG.12. Then, the CPU 201 executes data communication at the processingtiming.

On the other hand, the image display 1 transmits its specificationinformation to the terminal 2 by the power-on processing shown in FIG. 9to share adjustment data and the like, and then shifts to setupprocessing in the operation mode shown in FIG. 16. In step S61, thedisplay CPU 101 determines the operation mode of the timing generator104. The display CPU 101 monitors whether the display modem 103 detectsa synchronization signal from the terminal 2 at timing corresponding tothe determined operation mode.

If the display modem 103 receives a synchronization signal from theterminal 2, the display CPU 101 outputs a regeneration SYNC signal andregeneration CLK signal. Then, the display CPU 101 advances from stepS62 to step S63 to generate transmission processing timing. For example,the CPU 101 generates an enable signal and the like for time-divisionmultiplexing of respective processing data, such as communicationdirection control timing to the display modem 103, interrupt signalgeneration timing to the display CPU 101 for commandtransmission/reception, and command data processing timing for the videosignal processor 105, audio signal processor, and display CPU 101.

In step S64, the display CPU 101 generates signal processing timing tocontrol a video signal to be received and the like to a receivablestate. After that, the CPU 101 performs reception control of a videosignal and audio signal (acoustic signal) and transmission/receptioncontrol of command data in accordance with this setup processing.

Upon the completion of setup processing, the terminal 2 performs datacommunication with the image display 1 synchronized with synchronizationsignals corresponding to generation of display data from the input I/F220.

Data communication timing between the terminal 2 and image display 1when an image of the NTSC format is input to the input I/F 220 and thedisplay panel 110 of the image display 1 has 852 dots×480 dots will bedescribed with reference to FIGS. 17 and 18. FIG. 17 is a timing chartshowing data communication control timing in a vertical synchronizationsignal generation period in the image display 1 and terminal 2 of thefirst embodiment, and FIG. 18 is a timing chart showing datacommunication control timing in a horizontal synchronization signalgeneration period in the image display 1 and terminal 2 of the firstembodiment.

In the first embodiment, as shown in FIG. 17, effective video data aretransmitted at the above-mentioned timing in synchronism with a VSYNCsignal and HSYNC signal. Since the display panel 110 has 852 dots×480dots in this embodiment, video data of 480 lines is transmitted/receivedat an interval between VSYNC signals.

In this embodiment, a DIR signal for controlling the communicationdirection is kept at high level except for a predetermined periodimmediately before VSYNC signal output timing. Accordingly, the commandcommunication direction is set to a transmission direction from theterminal 2 to the image display 1 in principle.

As an example of a command transmission/reception timing, VSYNC signaloutput timing is set as actual command transmission timing from theterminal 2 to the image display 1 using the fact that the transmissiontiming of effective video data is not set before and after the VSYNCsignal in order to ensure blanking timing. A transmission command enablesignal is output at predetermined timing between HSYNC signals at theVSYNC signal timing shown in FIG. 17. Note that FIG. 17 shows an exampleof transmitting a command of two blocks.

A command transmission timing from the image display 1 to the terminal 2is set to predetermined timing between HSYNC signals of two cyclesimmediately before the VSYNC signal timing, and a reception commandenable signal is output. Note that the image display 1 has atransmission/reception enable timing opposite to that of FIG. 17.

As shown in FIG. 18, the data transmission timing between HSYNC signalsuses an interval from HSYNC signal timing to video data communicationtiming, and L-channel audio data and R-channel audio data aretransmitted/received. At subsequent video data enable timing, image dataof 852 dots of one horizontal line is transmitted/received.

In this manner, according to the first embodiment, video data andacoustic data (audio data) to be displayed between VSYNC signals aremultiplexed for transmission/reception. If necessary, command data canalso be multiplexed for transmission/reception.

The above processing determines the timing of various control operationsto be executed at the terminal of this embodiment. Detailed adjustmentcontrol conforming to the specifications of the image display 1 will beexplained.

The transmission format is determined by characteristic data(resolution, pixel layout, screen aspect ratio, and refresh rate) of thedisplay panel 110. (The number of display lines+necessary blankingperiod) is set in the refresh rate (vertical sync frequency) todetermine a horizontal period. For example, 480 display lines and ablanking period of 45 lines are set in a period of 60 Hz.

If the transmission specification suffices to be the same as the inputsignal specification, data can be output without performing any specialconversion processing. When, however, a large amount of command data(control signals) need to be communicated, the blanking period may beprolonged.

The (number of display pixels+audio data to be multiplexed+necessaryblanking period) in one horizontal period is calculated to determine thefrequency of master CLK. Also in this case, if the transmission formatsuffices to be the same as the input signal format, the CLK signal ofinput information can be used without any change. However, if theblanking period in the input format is long, and the frequency is to bedecreased, an input CLK signal is changed, as needed.

The layout of video data/audio data in the horizontal period and thelayout of video data/control signal data in the vertical period aredetermined. If necessary, the terminal 2 transmits the determinedcontents as command data to the image display. The terminal 2 and imagedisplay 1 recognize the command data and share the recognized results.

In determining the refresh rate, this rate is set to the refresh rate ofan input signal to the input I/F 220 when the refresh rate of the imagedisplay 1 is sufficiently high. However, if the user requests a higherrefresh rate by an instruction via the user I/F 230 or 130, the refreshrate may be increased. For example, the refresh rate is increased inconverting a signal of the interlaced scheme into a signal of theprogressive scheme in order to improve flicker characteristics.

When the screen aspect ratio of the display panel 110 does not coincidewith the aspect ratio of an input signal to the input I/F 220, thedisplay mode can be changed by automatic determination or a userrequest.

In this way, the transmission specification is determined. An example ofchanging the transmission specification in accordance with thespecifications of the display panel 110 of the image display 1 connectedto the terminal 2 in the first embodiment will be described below.

FIG. 19 shows an example when the display panel 110 has 852 dots×480dots (R, G, and B stripes). In this case, as shown in FIG. 19, thevertical sync (VSYNC) frequency is about 60 Hz, 525 HSYNC signals aregenerated during one VSYNC period, and 480 HSYNC periods from the 36thHSYNC signal among the 525 HSYNC signals upon generation of a VSYNCsignal are set as an effective video data period.

The horizontal synchronization signal (HSYNC) has a frequency of 31.5kHz, and the clock signal (CLK signal) has a frequency of 33.1 MHz.During one HSYNC period, 1,052 CLK signals are generated. Video data iscommunicated in synchronism with 852 clock signals from the 126th CLKsignal among the 1,052 CLK signals upon generation of an HSYNC signal.

FIG. 20 shows an example when the display panel 110 has 640 dots×480dots (R, G, and B stripes). In this case, as shown in FIG. 20, thevertical sync (VSYNC) frequency is about 60 Hz, 525 HSYNC signals aregenerated during one VSYNC period, and 480 HSYNC periods from the 36thHSYNC signal among the 525 HSYNC signals upon generation of a VSYNCsignal are set as an effective video data period.

The horizontal synchronization signal (HSYNC) has a frequency of 31.5kHz, and the clock signal (CLK signal) has a frequency of 24.9 MHz.During one HSYNC period, 790 CLK signals are generated. Video data iscommunicated in synchronism with 640 clock signals from the 95th CLKsignal among the 790 CLK signals upon generation of an HSYNC signal.

FIG. 21 shows an example when the display panel 110 has 1,365 dots×768dots (R, G, and B stripes). In this case, as shown in FIG. 21, thevertical sync (VSYNC) frequency is about 60 Hz, 807 HSYNC signals aregenerated during one VSYNC period, and 768 HSYNC periods from the 31stHSYNC signal among the 807 HSYNC signals upon generation of a VSYNCsignal are set as an effective video data period.

The horizontal synchronization signal (HSYNC) has a frequency of 48.4kHz, and the clock signal (CLK signal) has a frequency of 81.5 MHz.During one HSYNC period, 1,685 CLK signals are generated. Video data iscommunicated in synchronism with 1,365 clock signals from the 201st CLKsignal among the 1,685 CLK signals upon generation of an HSYNC signal.

When the image display 1 has a memory for temporarily storing video datatransferred to the image display 1, the display timing of the displaypanel 110 and the video data transfer timing need not always coincidewith each other in the above manner. Video data may be transferred bychanging the number of clocks (CLK) during the blanking period todecrease the clock frequency. For example, as shown in FIG. 22, thefrequency of the clock signal (CLK signal) may be set to 67.8 MHz so asto generate 1,400 CLK signals during one HSYNC period, and video data of1,365 dots may be transferred during the HSYNC period.

For a low transfer rate (clock signal frequency), the image display 1becomes highly resistant to noise, and a decrease in display quality canbe effectively prevented. The terminal 2 of the first embodimentdetermines the processing specification of an audio signal in accordancewith the speaker specifications of the image display 1.

For example, when the image display 1 is equipped with only one monauralspeaker 123, audio data is data of one channel.

If the image display 1 is equipped with two speakers 123, and the audioamplifier 122 has independent amplifier circuits of two channels for therespective speakers, audio data are right (R) and left (L) stereo audiodata. For multichannel surround data, the terminal 2 determines totransfer audio data of necessary channels in accordance with thesurround specification.

When an input signal to the input I/F 220 is a digital input,asynchronous audio signals are synchronized and horizontallymultiplexed. Alternatively, communication audio data can be changed inaccordance with a user request (e.g., the user wants to listen to a mainsound from right and left speakers).

A detailed processing method of video data is also determined inaccordance with specific data of the image display. For example, thequantization precision is determined in correspondence withcharacteristic data of the display panel 110 so as to make the number ofgray levels match the display gray level.

Not only the number of gray levels but also the gray levelcharacteristic undergo processing such as nonlinear transformation so asto make the gamma (γ) characteristic of the display device match theemission characteristic of the display panel 110. For example, theemission luminance controlled by PWM modulation exhibits a linearcharacteristic, so that only reverse γ transformation is performed.

As for the color temperature of the display device, the reproduced whitecolor temperature changes depending on the specifications of thedisplay. Thus, the R/G/B balance is adjusted to obtain a desired colortemperature. The enhancer is optimized in correspondence with the screensize and resolution. Note that processing also changes depending on aninput signal or user request.

Similarly, the resolution is converted to match a changed resolution,pixel layout, display aspect ratio, refresh rate, input signal format,or transmission format.

The user I/Fs 130 and 230 of the above-described embodiment enable imagequality adjustment and acoustic adjustment by inputting an instructionto the operation panel of the apparatus. At the same time, the user I/Fs130 and 230 enable remote control using, e.g., a system remotecontroller.

More specifically, the terminal 2 and image display 1 share useradjustment data (remote controller or key switch operation), shareoperation input results by exchanging command data, to meet a userrequest in either of the terminal 2 and image display 1. Communicationcommand data of the first embodiment controls to transfer even anoperation input result (remote controller or key switch operation) foreither user I/F to the terminal 2 and image display 1. The terminal 2and image display 1 can be similarly controlled even by an instructionto either user I/F.

For example, channel selection of the tuner 240 of the terminal 2 can bedone by an instruction input to the user I/F 130 of the image display 1.

In this embodiment, it is determined in accordance with thespecifications of the image display 1 whether better adjustment can beachieved by the video signal processor 105 or panel driver 106 of theimage display 1 or the video signal processor 205 of the terminal 2. Theadjustment authorization is assigned to one determined to be optimum. Inother words, when the terminal 2 and image display 1 have the sameadjustment function, they exchange data for determining the one thatexecutes adjustment, and perform optimal adjustment.

Distribution results of the adjustment authorization in the firstembodiment are as follows:

-   -   _Contrast adjustment is done by the terminal 2.    -   _Color adjustment is done by the terminal 2.    -   _Color temperature adjustment is done by the image display 1.    -   _Volume adjustment is done by the image display 1.    -   _Enhancer adjustment is done by the terminal 2.

According to distribution of these adjustment authorizations, theadjustment authorization is assigned to the image display 1 or terminal2 which easily performs adjustment for obtaining optimal results orbetter results. When one of the image display 1 and terminal 2 detectsan adjustment instruction for which no adjustment authorization isassigned, it does not execute any adjustment, and transfers at least theadjustment instruction detection result to the other having theadjustment authorization at the transmission timing of command data.

For an adjustment instruction for which the adjustment authorization isassigned, one of the image display 1 and terminal 2 executes adjustment,and transfers the adjustment results to the other.

Modification of First Embodiment

In the above-described first embodiment, video data, acoustic data(audio data), and command data are multiplexed such that acoustic datais multiplexed between video data enable timing by each HSYNC signal,and command data is multiplexed between HSYNC signals outside the videodata enable period between VSYNC signals, as shown in FIGS. 17 and 18.

However, the present invention is not limited to this multiplexingtiming. For example, audio data is communicated not divisionally atrespective HSYNC timing but at once every VSYNC timing.

FIG. 23 shows communication timing between the terminal 2 and imagedisplay 1 when audio data is communicated not divisionally at respectiveHSYNC timing but at once every VSYNC timing.

In the example shown in FIG. 23, audio data is communicated at once atinter-HSYNC timing between video data enable timing upon arrival of aVSYNC signal.

This communication timing is effective when the image display 1comprises a memory capable of temporarily holding audio data.

In the first embodiment, command data is multiplexed between HSYNCsignals outside the video data enable period between VSYNC signals.However, the present invention is not limited to this multiplexingtiming. For example, command data may be communicated divisionally atrespective HSYNC timing.

FIG. 24 shows communication timing between the terminal 2 and imagedisplay 1 when command data is communicated not at once every VSYNCtiming but divisionally at respective HSYNC timing.

In the example shown in FIG. 24, command data is communicateddivisionally in units of, e.g., words at timing between video dataenable timing after the audio data communication timing. In this case,command data of one packet is transmitted in several HSYNC periods.

This communication timing is suitable in communicating command datawhich must be communicated emergently or in a small amount of entirecommunication command data so as to communicate only changed data amongvarious data.

In the example shown in FIG. 17, the command data communication timingis set to, e.g., two HSYNC periods and VSYNC signal arrival periodimmediately before arrival of a VSYNC signal. However, the presentinvention is not limited to this. Command data can be communicated overthe period except for the video data enable period and audio datacommunication period. FIG. 25 shows communication timing between theterminal 2 and image display 1 in this control.

In the example shown in FIG. 25, a necessary number of command data canbe transmitted during the VSYNC period. This communication timing iseffective when not only changed information but also the wholeinformation is necessarily communicated as command data. Even if acommunication error occurs or a packet is discarded, the influence canbe minimized.

Second Embodiment

In the first embodiment, the terminal 2 is connected to one imagedisplay 1, and the image display 1 is not connected to any other device.However, the present invention is not limited to this. Another optionaldevice may be connected to one terminal or image display. For example, avideo printer is connected to hard-copy image data displayed on theimage display. Note that the second embodiment is the same as the firstembodiment except for the following arrangement, and a detaileddescription thereof will be omitted.

The second embodiment according to the present invention in whichanother optional device, e.g., a video printer is connected to oneterminal or image display will be described with reference to FIGS. 26to 28. In the second embodiment, the same reference numerals as in thefirst embodiment denote the same parts, and a detailed descriptionthereof will be omitted. Also in the second embodiment, exchange ofvarious data between the image display 1 and terminal 2 is the same asin the first embodiment.

FIG. 26 is a block diagram for explaining a basic system arrangement ofthe second embodiment according to the present invention. As shown inFIG. 26, in the second embodiment, a terminal 800 performs necessaryconversion processing or the like for an input signal in accordance withthe specifications of an image display 1000, and outputs the processedsignal to the image display 1000 via a connection means 900.

The image display 1000 is designed to allow connecting an optionaldevice 1100. The terminal 800 is adapted to transfer data to theoptional device 1100 via the image display 1000.

In the example of FIG. 26, the optional device 1100 is connected to theimage display 1000. The terminal 800 of the second embodiment is alsodesigned to allow connecting an optional device, and may be arranged asshown in FIG. 27. In the following description, the optional device canbe connected to both the terminal 800 and image display 1000. However,the present invention is not limited to this, and includes a case inwhich the optional device can be connected to only the image display1000 or terminal 800.

A detailed arrangement of the second embodiment shown in FIG. 26 or 27is shown in FIG. 28. FIG. 28 is a block diagram showing the detailedarrangement of the second embodiment. Referring to FIG. 28, only adifferent arrangement from that of the first embodiment shown in FIG. 2will be explained.

In the image display 1000, in addition to the arrangement shown in FIG.2, a connection line dedicated for the optional device 1100 is connectedto a connector 655 for the terminal 800. A signal through this dedicatedconnection line is input to an external modem 651. The external modem651 demodulates a signal from the terminal 800 to output the demodulatedsignal to an external I/F 653, and modulates a signal from the externalI/F 653 to output the modulated signal to the dedicated connection line.

The image display 1000 comprises an external timing generator 652.Control of the external I/F 653 and communication control with theterminal 800 using the external modem 651 are done under the control ofa display CPU 101.

The external I/F 653 interfaces the optional device 1100, e.g., a videoprinter via an external input/output terminal 654.

In the terminal 800, a signal processor 601 realizes both the functionsof the video signal processor 205 and audio signal processor 210 shownin FIG. 2. A terminal modem A 203 realizes the same function as theterminal modem 203 in FIG. 2. A terminal modem B 602 is used forcommunication with the optional device 1100 connected to the imagedisplay 1000.

A timing generator A 603 realizes the same function as the timinggenerator 204 in FIG. 2. A timing generator B 606 receives a clocksignal and synchronization signal from the timing generator A 603 underthe control of a terminal CPU 201. If necessary, the timing generator B606 outputs a control timing signal to the terminal modem B 602 or a D/Aconverter 607 in synchronism with the clock signal and synchronizationsignal.

The D/A converter 607 is adopted not for a case in which a device suchas a video printer is connected as the optional device 1100 and data isoutput to it, but for a case in which data input from the optionaldevice 1100 is transmitted to the terminal 800 via the external I/F 653and external modem 651. The D/A converter 607 D/A-converts data outputfrom the terminal modem B 602 and outputs the analog data to a terminaloutput terminal 609.

Instead, an output signal from the D/A converter 607 can be transmittedto the image display 1000 via a selector 608, the signal processor 601,and the terminal modem A 203.

Also in the second embodiment having this arrangement, when the terminal800, image display 1000, and optional device 1100 are powered on, theID, specifications, and adjustment data of the optional device 1100 areshared between the terminal 800 and optional device 1100 similarly topower-on processing of the first embodiment shown in FIGS. 8 and 9. Thedata transmission specification between the terminal modem B 602 andexternal modem 651 is determined similarly to processing in FIGS. 15 and16, and necessary optional device data is transmitted.

When the optional device 1100 is a video printer, video data to beprinted or print data for the optional device is output.

The optional device 1100 is a video printer in this example, but is notparticularly limited to this. For example, the optional device 1100 maybe a video output device such as a video cassette recorder. In thiscase, a video signal from the optional device 1100 is input to theexternal input/output terminal 654, and data is transmitted to theterminal 800 via the external I/F 653 and external modem 651.

In the terminal 800, the D/A converter 607 converts data received by theterminal modem B 602 into the same format as that of input data to theexternal input/output terminal 654 of the image display 1000, andoutputs the converted data to the external output terminal 609 of theterminal 800. For example, when the external input/output terminal 654of the image display 1000 and the external output terminal 609 of theterminal 800 comprise an RCA pin jack connector and DV connector, datais output from the terminal 800 with a signal format represented by aconnector used for the input of the image display 1000.

It is also possible to transmit a signal input to the externalinput/output terminal 654 of the image display 1000 to the terminal 800,process the signal by the signal processor 601 in the terminal 800 so asto match the specifications of the image display 1000, and send back theprocessed signal to the image display 1000 via the terminal modem A 203.

Third Embodiment

In the second embodiment, the dedicated modem and connection line areemployed for the optional device 1100 in order to connect the optionaldevice 1100. However, when the optional device is not one which need notemergently transmit/receive a large amount of information in real time,for example, when the optional device is a video printer, the dedicatedmodem and connection line need not be necessarily adapted for theoptional device 1100.

Even when the optional device is connected to the image display,information for the optional device is controlled to be multiplexed andcommunicated using the idle time of information communication betweenthe terminal and image display.

The third embodiment according to the present invention in whichcommunication between the optional device and terminal is executedduring the idle time of communication between the terminal and imagedisplay even when the optional device is connected to the image displaywill be described with reference to FIGS. 29 and 30. The thirdembodiment is the same as the above embodiments except for the followingarrangement, and a detailed description thereof will be omitted.

In the third embodiment, FIG. 29 is a block diagram showing thearrangement of the third embodiment according to the present invention,and FIG. 30 is a timing chart for explaining information communicationtiming in the third embodiment.

Also in the third embodiment shown in FIG. 29, the terminal and imagedisplay have the same basic arrangements as in the first embodimentshown in FIG. 2. In the third embodiment shown in FIG. 29, the followingunits are added to a terminal 1400 and image display 1500 in addition tothe arrangements of FIG. 2.

More specifically, the image display 1500 comprises an external I/F 1510which interfaces with an optional device 1100 and receives communicationdata from a display modem 103 to the optional device 1100. The terminal1400 comprises an external I/F 1410 which interfaces with an optionaldevice 1100 and receives communication data from a terminal modem 203 tothe optional device 1100.

The input/output timing from the terminal modem 203 (display modem 103)is controlled to the timing shown in FIG. 30.

Compared to the control timing of the first embodiment shown in FIG. 17,the control timing shown in FIG. 30 controls to communicate atransmission command enable signal from the terminal modem 203 of theterminal 1400 to the optional device 1100 using an HSYNC period A shownin FIG. 30 as transmission timing to the image display 1500, and aperiod B except for effective video data communication timing andcommand data reception timing from the image display 1500 when a DIRsignal is at low level.

For example, when the optional device 1100 is connected to the imagedisplay 1500, a timing generator 104 outputs, to the external I/F 1510at the timing B shown in FIG. 30, a timing signal for receivingdemodulated data from the display modem 103 and transmitting the data tothe optional device 1100.

In the example shown in FIG. 30, data of about 20 lines can be ensuredduring the period B to transmit 1-frame data in units of 20 lines atabout 60 Hz within 1 sec. In divisionally transmitting data in thisfashion, a line number is desirably added to the head of everytransmission of 1-line data in order to determine transmitted data.

If the image display additionally comprises a frame memory, it ispossible to write data transferred to this optional device in the framememory, and after all the data are written, transfer the data to theconnected optional device. If the image display holds display data toits display screen in the frame memory, the image display may receivefrom the terminal a command for outputting the held data to the optionaldevice.

The image display equipped with the external output frame memory canoutput information conforming to the specifications of an optionaldevice connected to the image display. Limitations on the connectedoptional device can be greatly reduced, resulting in high versatility.

When the external I/F 1510 receives a command data transmission requestfrom the optional device 1100, the external I/F 1510 instructs a displayCPU 101 to set command data transmission timing from the optional device1100 during the period B or to transmit command data from the optionaldevice 1100 mixedly in transmission during the command data transmissionperiod from the image display 1500 to the terminal 1400. In this case,the ID of the optional device 1100 is attached to a header in order todetermine the transmission source.

On the other hand, when the optional device 1100 is connected to theterminal 1400, a timing generator 204 outputs, to the external I/F 1410at the timing B shown in FIG. 30, a timing signal for receivingdemodulated data from the terminal modem 203 and transmitting the datato the optional device 1100.

Upon reception of a command data transmission request from the optionaldevice 1100, the external I/F 1410 instructs a terminal CPU 201 torequest reception of command data from the optional device 1100.

Under this control, the optional device can be controlled without usingany modem for the optional device.

Fourth Embodiment

In the above-mentioned embodiments, one image display is connected tothe terminal 2. However, the present invention is not limited to this,and includes a case in which a plurality of image displays can beconnected to one terminal. The present invention further includes a casein which an optional device is connected, as described in the second orthird embodiment.

The fourth embodiment according to the present invention in which aplurality of image displays can be connected to the terminal will bedescribed with reference to FIGS. 31 to 33. The fourth embodiment is thesame as the above embodiments except for the following arrangement, anda detailed description thereof will be omitted.

FIG. 31 is a block diagram showing the arrangement of the fourthembodiment according to the present invention. FIG. 32 is a timing chartfor explaining communication control during the VSYNC period between theterminal and image display of the fourth embodiment. FIG. 33 is a timingchart for explaining communication control during the HSYNC periodbetween the terminal and image display of the fourth embodiment.

The whole arrangement of the fourth embodiment will be explained withreference to FIG. 31. In FIG. 31, reference numeral 1600 denotes aterminal capable of connecting two image displays; 1700, an imagedisplay A; and 1800, an image display B. The image display A 1700 andimage display B 1800 may have the same arrangement. FIG. 31 shows onlythe detailed arrangement of the image display A 1700.

The image display A 1700 has the same arrangement as that of the imagedisplay 1 shown in FIG. 2, and the same reference numerals denote thesame parts.

The terminal 1600 has an arrangement for communicating with the imagedisplays 1700 and 1800 because it must transmit display information tothe two image displays 1700 and 1800.

The terminal 1600 comprises a terminal modem A 1602, signal processor A1604, and timing generator A 1606 for the image display A 1700, and aterminal modem B 1603, signal processor B 1605, and timing generator B1607 for the image display B 1800. For the image displays 1700 and 1800,a terminal CPU 1601 performs the same control as that for the imagedisplay of the first embodiment.

That is, the terminal CPU 1601 executes power-on processing shown inFIGS. 8 and 9 with the image displays 1700 and 1800, operation modesetup processing shown in FIGS. 15 and 16, and transmissionspecification determination processing and the like.

To display a common image on the respective image displays and output acommon acoustic output, the terminal shares an input source, and makesthe operations of each signal processor and timing generator match aconnected image display. To display different images on the respectiveimage displays, the terminal appropriately distributes input signals toan input I/F 220. Alternatively, a tuner 240 may be formed from doubletuners to display independent television programs on the image displays.

Also in this case, the terminal can share adjustment data with eachimage display, and a user instruction through the user I/F of the imagedisplay can be applied to, e.g., the tuner 240 of the terminal. Hence,the image display can be controlled without any spatial arrangement andoperation.

Remote controller input detection modes to a user I/F 230 of theterminal 1600 may be set detectable for two remote controllers, and therespective detection modes may be distributed to the image displays.This enables controlling the terminal with the remote controllers.

When an optional device can be connected to each image display or theterminal, the arrangement shown in FIG. 29 for the optional device maybe added to the arrangement shown in FIG. 31 to perform the same controlas in FIG. 29. Instead, the arrangement shown in FIG. 28 may be added toeach image display or the terminal.

Communication control timing between the terminal 1600 and imagedisplays 1700 and 1800 of the fourth embodiment having the abovearrangement will be described with reference to FIGS. 32 and 33.

Communication control during the VSYNC period (vertical period) in thefourth embodiment will be explained with reference to FIG. 32. Forexample, the terminal 1600 of the fourth embodiment outputs atransmission command 1 enable signal for permitting command transmissionto the image display A 1700 during the first HSYNC period (horizontalperiod) at arrival of a VSYNC signal during the VSYNC period (verticalperiod). Then, the terminal 1600 outputs a transmission command 2 enablesignal for permitting command transmission to the image display B 1800during the next HSYNC period.

During a predetermined HSYNC period after the effective video datatransmission timing, the terminal 1600 outputs a reception command 1enable signal for permitting command reception from the image display A1700. Then, during the subsequent HSYNC period, the terminal 1600outputs a reception command 2 enable signal for permitting commandreception from the image display B 1800. Accordingly, commandcommunication between the image displays 1700 and 1800 can becontinuously processed by the terminal CPU 1601 without any overlap.

Communication control during the HSYNC period (horizontal period) in thefourth embodiment will be explained with reference to FIG. 33.

In the example of FIG. 33, the upper timing charts show an example inwhich a display panel 1100 of the image display A 1700 has 852 dots×480dots, as described with reference to FIG. 19 in the first embodiment,and acoustic signals of two channels are transmitted to stereo speakersof two L and R channels. The lower timing charts show an example inwhich a display panel 1100 of the image display B 1800 has 640 dots×480dots, as described with reference to FIG. 20 in the first embodiment,and acoustic signals of four channels are transmitted to speakers offour channels.

Since the terminal 1600 has only one terminal CPU 1601, communication ofcommand data with each image display is controlled to preventcommunication timing from overlapping each other, as shown in FIG. 32.To the contrary, the terminal 1600 comprises the signal processor andtiming generator for each image display. Therefore, the terminal 1600 ofthe fourth embodiment can perform video data communication without anyerror even with different communication specifications for respectiveimage displays.

According to the fourth embodiment, a plurality of image displays can beconnected to the terminal. Still further, with transmissionspecifications suitable for respective image displays without anyspecial arrangement, display data and audio data can be transmitted toeven image displays having different display specifications.

Fifth Embodiment

In the fourth embodiment, the terminal 2 comprises informationcommunication modems for two connected image displays. However, thepresent invention is not limited to this, and includes an arrangement inwhich the terminal can be connected to one image display, and the imagedisplay can be connected to another image display or the like. Thepresent invention also includes an arrangement in which an optionaldevice is connected, as described in the second or third embodiment.

The fifth embodiment according to the present invention in which theterminal is adapted to control a plurality of image displays via animage display, and the image display can be connected to still anotherimage display or the like will be described with reference to FIGS. 34to 38. The fifth embodiment is the same as the above embodiments exceptfor the following arrangement, and a detailed description thereof willbe omitted.

FIG. 34 is a block diagram showing the arrangement of the fifthembodiment according to the present invention. FIG. 35 is a view forexplaining a packet structure used in the fifth embodiment. FIG. 36 is aview for explaining the detailed structure of an address command shownin FIG. 35. FIG. 37 is a block diagram showing a state in which aplurality of image displays are connected in the fifth embodiment. FIG.38 is a flow chart for explaining command data reception processing ofthe image display.

In the fifth embodiment, the hardware arrangement is simplified as muchas possible, and the communication control sequence is changed to allowconnecting many image displays to one terminal.

For this purpose, a terminal 2000 may adopt the same hardwarearrangement as the first or third embodiment. When the terminal 2000adopts the same arrangement as the third embodiment, the terminal 2000can be connected to an optional device, e.g., printer via an externalI/F.

In addition, the image display of the fifth embodiment includes a drivercircuit 150 in comparison with the image display 1 of the firstembodiment shown in FIG. 2. The driver circuit 150 can be connected toanother image display.

Like an image display A 2200, an external I/F 151 may be employed toallow connecting an optional device to the image display, similar to thethird embodiment. In place of the arrangement shown in FIG. 34, theterminal may take the same arrangement as the terminal 1600 of thefourth embodiment shown in FIG. 31. Also in this case, a transmissioncontrol sequence (to be described later) can be applied. Thetransmission control sequence will exemplify a case in which theterminal can be connected to two image displays, and either imagedisplay is connected to a printer as an optional device.

In the fifth embodiment, the image display performs only control oftransferring communication data from the terminal to the next imagedisplay via the driver circuit 150, and a detailed description of thehardware will be omitted.

Note that all the communication data output from the terminal 2000 arereceived by the modems of all the connected apparatuses. Thus, eachapparatus employs an arrangement of determining whether data is directedto the apparatus on the receiving side.

The fifth embodiment, therefore, uses a packet having the structureshown in FIG. 35. The packet structure shown in FIG. 35 includes adestination address 531 and source address 532 in addition to the packetstructure of the above embodiments shown in FIG. 10 or 11.

FIG. 36 shows the detailed structure of the address field shown in FIG.35. As described in the above embodiments, video data is made up of 24bits; and command data, 16 bits.

In the fifth embodiment, 16-bit command data is divided into upper 8bits and lower 8 bits. The upper 8 bits represent address data whichspecifies devices (image display A 2200 and image display B 2100 in theexample of FIG. 34) directly connected to the terminal 2000.

The lower 8 bits represent address data which specifies a device(optional device 1100 connected to the image display A 2200 in theexample of FIG. 34) subsidiary to the device specified by the upper 8bits.

Transmission control from the terminal to each connected device usingthis command communication packet will be explained with reference tothe flow chart of FIG. 38. For descriptive convenience, the flow chartof FIG. 38 will be described by exemplifying the connection state shownin FIG. 37.

In FIG. 37, reference numeral 2500 denotes a terminal with two portswhich has the same arrangement as the terminal 1600 shown in FIG. 31;2600, a display A having the same arrangement as the image display A2200 in FIG. 34; 2650, a printer as an optional device connected to thedisplay A 2600 via, e.g., the external I/F 151; 2700, a display Bconnected to the driver circuit 150 of the display A 2600; and 2800, adisplay C connected to the terminal 2500. Note that a numerical value atthe upper right portion of each unit is an address assigned to the unit.

Each display connected to the terminal 2500 monitors reception ofcommand data (command packet) in step S101 of FIG. 38. Upon reception ofcommand data, the display shifts to step S102 to check whether the upperaddress shown in FIG. 36 is an address assigned to the display. Forexample, the display A 2600 shown in FIG. 37 checks whether the upperaddress is “H(01)”. If NO in step S102, the display returns to step S101without performing any processing, and waits for reception of the nextcommand. Packet information from the terminal 2500 is also automaticallytransmitted to the next image display via the driver circuit 150. Solong as the driver 150 is kept driving, packet information isautomatically transferred to another image display connected to thisdisplay. Thus, the display need not perform further control.

If YES in step S102, the display advances to step S103 to check thelower 8-bit address and whether the packet is directed to the display.For example, the display A 2600 in FIG. 37 determines that the packet isdirected to it for lower 8 bits of “00”, and otherwise the packet isdirected to a subsidiary device, e.g., the printer 2650.

If NO in step S103, the display advances to step S104 to relay thereception packet to a connected optional device. For example, thedisplay transmits the packet from the display modem to the connectedoptional device via the external I/F. Then, the display returns to stepS101 to wait for reception of the next command.

If YES in step S103, the display advances to step S105 to check whetherto be in an OFF state (power-off state of the display panel). If YES instep S105, the display advances to step S106. The display sets theterminal address to the destination address and the display address tothe source address at command transmission timing from the display tothe terminal. The display generates and transmits a response packetincluding command data representing the power-off state. Then, thedisplay returns to step S101.

If NO in step S105, the display shifts to step S107 to analyze thereception packet. In step S108, the display checks whether the commandis an invalid one the display cannot process. If NO in step S108, thedisplay shifts to step S109 to execute processing corresponding to theanalyzed command. Then, the display returns to step S101.

If YES in step S108, the display shifts to step S110. The display setsthe terminal address to the destination address and the display addressto the source address at the next command transmission timing from thedisplay to the terminal. The display generates and transmits a responsepacket including command data “NAK”. Then, the display returns to stepS101.

If the display has a request to be transmitted to the terminal, thedisplay sets the terminal address to the destination address and thedisplay address to the source address at the next command transmissiontiming from the display device to the terminal. Then, the displaygenerates and transmits a transmission packet including transmissioncommand data.

When the display receives a transmission request from a connectedoptional device and does not have any transmission request, the displaysets the terminal address to the destination address and the address ofthe connected device to the source address at the next commandtransmission timing from the display to the terminal. Then, the displaygenerates and transmits a transmission packet including transmissioncommand data.

According to the fifth embodiment, a necessary number of image displayscan be connected to one terminal.

In the fifth embodiment, respective image displays receive common data.Display data can be transmitted to a necessary number of image displayswithout any change as far as they have common specifications.

If the image displays have different display specifications, aresolution conversion function is added to, e.g., the video signalprocessors of each image display and the terminal. This greatly reduceslimitations on the specifications of a connected image display.

For example, the terminal converts input video data through the inputI/F into high-resolution image information or image information with aresolution guaranteed for transmission quality, and transmits the imageinformation to each image display. The image display converts thereceived image information with a predetermined resolution into anappropriate resolution, and then displays the resultant information.

Sixth Embodiment

In these embodiments, the terminal and image display have completelyindependent arrangements and control operations. However, the presentinvention is not limited to this. For example, a necessary processingsequence in processing display information output from the image displayby the image display can be transferred from the terminal to the imagedisplay, as needed.

This arrangement realizes reliable feedback to the image display wheninformation cannot be properly displayed only by the normal function ofthe image display or the apparatus has been improved. The sixthembodiment according to the present invention in which the terminal isadapted to transfer a predetermined control sequence to the imagedisplay will be described with reference to FIGS. 39 to 41. The sixthembodiment is the same as the above embodiments except for the followingarrangement, and a detailed description thereof will be omitted.

FIG. 39 is a block diagram showing the arrangement of the sixthembodiment according to the present invention. FIG. 40 is a flow chartshowing download processing of the terminal in the sixth embodiment.FIG. 41 is a flow chart showing download processing of the image displayin the sixth embodiment.

In the sixth embodiment, in addition to the arrangement of the firstembodiment shown in FIG. 2, a terminal 2 comprises a program memory 260,and an image display 1 comprises a program memory 160 for storing acontrol program downloaded to a display CPU 101. The program memory 160is a nonvolatile memory, whereas the program memory 260 is a rewritablememory such as an EEPROM, flash memory, or SRAM backed up using abattery. The remaining arrangement is the same as in FIG. 2, and adetailed description thereof will be omitted.

The sixth embodiment having this arrangement executes processing inFIGS. 40 and 41 subsequent to, e.g., power-on processing shown in FIGS.8 and 9.

In step S150 of FIG. 40, the terminal 2 requests the image display 1 totransmit a program ID command representing the program version. In stepS151, the terminal 2 analyzes a sent-back program ID and compares itwith a program ID stored in the program memory 260. If the program ID ofthe image display 1 has the same version as the program ID of theterminal 2, the terminal 2 determines in step S152 that the program neednot be downloaded, and shifts to operation mode setup processing shownin FIG. 15.

If the program ID of the image display 1 is different from the programID of the terminal 2, the terminal 2 determines in step S152 that theprogram must be downloaded. The terminal 2 shifts to step S153 totransmit a program download request to the image display 1. The terminal2 checks a response from the image display 1 and whether the program canbe downloaded. If the program cannot be downloaded due to any reason orthe image display 1 does not comprise the program memory 160, theterminal 2 receives a download disable response. In this case, theterminal 2 shifts to operation mode setup processing shown in FIG. 15without downloading the program, and receives hardware specificationsand adjustment data. In this case, the terminal 2 may use afunction-limited control program to display data with a minimumfunction.

If the terminal 2 receives a download enable response in step S154, theterminal 2 advances to step S155 to download a given amount of programwhich can be transmitted at the next transmission timing. Then, theterminal 2 checks in step S156 whether download is completed. If NO instep S156, the terminal 2 returns to step S155 to download a givenamount of program which can be transmitted at the next transmissiontiming.

In this way, the terminal 2 sequentially downloads the program. Afterthe entire program is downloaded, the terminal 2 shifts from step S156to operation mode setup processing shown in FIG. 15.

On the other hand, the image display 1 monitors reception of a commandfrom the terminal 2 in step S161 shown in FIG. 41. If the image display1 detects command reception, it advances to step S162 to check whetherthe command is a transmission request command for the program IDcommand. If YES in step S162, the image display 1 advances to step S163to send back to the terminal 2 a program ID representing the version ofa program stored in the program memory 160.

If NO in step S162, the image display 1 advances to step S164 to checkwhether to have received a download request command. If NO in step S164,the image display 1 executes processing corresponding to the receptioncommand.

If YES in step S164, the image display 1 advances to step S165 to checkwhether the program can be downloaded. If the program cannot bedownloaded for any reason or the image display 1 does not comprise theprogram memory 160, the image display 1 determines that the programcannot be downloaded, and shifts to step S166 to send back a downloaddisable response to the terminal 2. Then, the image display 1 returns tostep S161.

If YES in step S165, the image display 1 advances to step S167 to sendback a download enable response. Then, the image display 1 downloads theprogram transmitted from the terminal 2 in step S168. In step S169, theimage display 1 checks whether download is completed. If NO in stepS169, the image display 1 returns to step S168 to download a givenamount of program which can be transmitted at the next transmissiontiming.

The image display 1 sequentially downloads the program. After the entireprogram is downloaded, the image display 1 shifts from step S169 tooperation mode setup processing shown in FIG. 16.

The program downloaded in this manner is a group of program macrocommands in display control performed by the image display 1. It isdesirable that the control program is written in the C language, and theterminal 2 sequentially translates and executes the control programwritten in the C language.

In this case, the control program can be executed regardless of themachine language of the CPU of the terminal 2. Note that the controlprogram is not limited to the C language.

As described above, according to the sixth embodiment, reliable feedbackto the image display is realized when information cannot be properlydisplayed only by the normal function of the image display or theapparatus has been improved.

Further, the terminal 2 is adapted to execute a control program matchingthe characteristics of the image display 1. For example, for a smalldisplay, the menu display function is reduced, and control is donemainly by a remote controller. For a large display, a visual I/F such asan icon is adopted in addition to a character menu.

Seventh Embodiment

In the above embodiments, the terminal and image display are adjusted inaccordance with a user instruction through the user I/F. However, thepresent invention is not limited to this. It is also possible to detectthe environment by the image display and adjust the image display andterminal in accordance with the detection results. The seventhembodiment according to the present invention in which the environmentcan be detected will be described with reference to FIGS. 42 to 45. Theseventh embodiment is the same as the above embodiments except for thefollowing arrangement, and a detailed description thereof will beomitted.

FIG. 42 is a block diagram showing the arrangement of the seventhembodiment according to the present invention. FIG. 43 is a view showinga layout of respective units in the seventh embodiment. FIG. 44 is aflow chart showing control of the image display upon detecting anenvironmental change in the seventh embodiment. FIG. 45 is a flow chartshowing control of the terminal upon detecting an environmental changein the seventh embodiment.

In the seventh embodiment shown in FIG. 42, in addition to thearrangement of the fourth embodiment shown in FIG. 31, a terminal 1600comprises a telephone use detector 271 for detecting use/non-use of atelephone set, and each of image displays 1700 and 1800 comprises abrightness detector 171 for detecting the ambient brightness of theimage display, a noise detector 172 for detecting volume (noiseintensity), and a color temperature detector 173 for detecting theambient color temperature. The remaining arrangement is the same as inFIG. 31, and a detailed description thereof will be omitted. Note thatthe image display B 1800 comprises identical detectors to those of theimage display A 1700.

The example of FIG. 42 will be described. These detectors can be appliedto the above-described embodiments.

For example, as shown in FIG. 43, the terminal 1600 is installed at thecorner of a living room, the display A 1700 as a large-size wall-mountedmonitor is mounted on the wall of the living room, and the display B1800 as a small-size monitor is installed in a bed room. In thissituation, the installation environment may greatly change between therespective displays, so that it is improper to apply the same adjustmentresults to both the displays. Further, only user adjustment does notalways provide the optimal image quality for appreciation. For thisreason, the seventh embodiment employs display and terminal environmentdetectors to perform adjustment matching their environments.

Control of the image display will be explained with reference to FIG.44. FIG. 44 is a flow chart showing control of the image display upondetecting an environmental change in the seventh embodiment.

The image display performs the following control. More specifically, adisplay CPU 101 performs processing coping with a predetermined changeor more detected by each detector. In the following description, theadjustment authorizations of adjustment items are assigned as describedin the first embodiment.

In step S201, the display CPU 101 checks whether the brightness detector171 detects a predetermined change or more. If Y (YES) in step S201, thedisplay CPU 101 advances to step S202 to inform the terminal 1600 of thedetection result. This is because the terminal 1600 has an adjustmentauthorization such as contrast adjustment for coping with brightnesschanges, as described above. If N (NO) in step S201, the display CPU 101shifts to step S203.

In step S203, the display CPU 101 checks whether the noise detector 172detects a predetermined change or more. If Y in step S203, the displayCPU 101 advances to step S204 to inform the terminal 1600 of thedetection result. The image display has an adjustment authorization forvolume adjustment. However, the volume must be controlled not toincrease during the use of a telephone set owing to the followingreason, so that the detection result is transmitted to cause theterminal to detect whether the telephone set is being used. After that,the volume is adjusted in accordance with a volume adjustmentinstruction from the terminal. This control is done by general commandprocessing.

When the terminal requests transmission of a command representingwhether the telephone set is being used, or the use of the telephone setis always informed, the display CPU 101 suffices to performcorresponding volume adjustment and transmit only the volume adjustmentresult.

The display CPU 101 joins a flow of N in step S203, and shifts to stepS205.

In step S205, the display CPU 101 checks whether the color temperaturedetector 173 detects a predetermined change or more. If Y in step S205,the display CPU 101 advances to step S206 to adjust, e.g., the paneldriver 106 of the image display, and increase the color temperature fora fluorescent lamp or decrease it for an incandescent lamp.

The display CPU 101 informs the terminal 1600 of the adjustment resultin step S207 and returns to step S201.

Control of the terminal will be described with reference to FIG. 45.FIG. 45 is a flow chart showing control of the terminal upon detectingan environmental change in the seventh embodiment. The terminal performsthe following control.

As shown in FIG. 45, the terminal 1600 monitors reception of commanddata from the image display in step S211. If N in step S211, theterminal 1600 advances to step S212, and monitors an output from thetelephone use detector 271 of the terminal 1600 to determine whether theuse condition of the telephone set changes. Although only one telephoneuse detector 271 is illustrated in FIG. 42, the use conditions of aplurality of telephone sets can be detected. This can be realized by aunit having a known telephone use detection function of detecting the DCloop formation state of a telephone set and determining whether thetelephone set is being used. If N in step S212, the terminal 1600returns to step S211.

If Y in step S211, the terminal 1600 advances to step S213 to checkwhether the command informs it of an environmental change. If N in stepS213, the terminal 1600 executes corresponding processing.

If Y in step S213, the terminal 1600 advances to step S214 to checkwhether brightness is detected. If Y in step S214, the terminal 1600advances to step S215 to perform adjustment coping with a brightnesschange, such as contrast control for which the terminal 1600 has anadjustment authorization.

In step S216, the terminal 1600 holds the adjustment results, andinforms a corresponding image display of it. If N in step S214, theterminal 1600 shifts to step S217.

In step S217, the terminal 1600 checks whether the noise level isdetected. If Y in step S217, or Y in step S212, the terminal 1600 shiftsto step S218 to check whether a telephone set in the same room as theimage display which informs the terminal 1600 of the environmentalchange is being used. If N in step S218, the terminal 1600 advances tostep S219 to instruct the image display to perform volume adjustmentcorresponding to the detected noise level; if Y in step S218, theterminal 1600 instructs the image display to decrease the volume.

The terminal 1600 shifts to step S221, and if it receives a colortemperature adjustment result, shifts to step S222. The terminal 1600holds the adjustment result, and returns to step S211.

Eighth Embodiment

In the above embodiments, the terminal and image display are directlyconnected using an interface cable. However, the present invention isnot limited to this, and also includes a case in which the terminal andimage display communicate with each other using radio waves at part ofthe interface cable.

The eighth embodiment according to the present invention in which theterminal and image display communicate with each other using radio wavesat part of the interface cable will be described with reference to FIG.46. The eighth embodiment performs optical communication using lightsuch as infrared rays at a radio section. However, optical communicationis not limited to this, various means such as ultrasonic waves and radiowaves may be used. The eighth embodiment is the same as the aboveembodiments except for the following arrangement, and a detaileddescription thereof will be omitted.

In the eighth embodiment, as shown in FIG. 46, the image displaycomprises an optical communication unit in place of an interfaceconnector with the terminal. The optical communication unit is made upof a light-emitting portion for transmitting command information to theterminal, and a light-receiving portion for receiving information fromthe terminal. A change in received light quantity at the light-receivingportion is detected as an electrical signal. The electrical signal isamplified by an amplifier and output to a display modem. Emission of thelight-emitting portion is controlled via a driver circuit in accordancewith a modulated signal from the display modem.

In the terminal, an optical communication unit almost identical to thatof the image display is attached to the distal end of the interfacecable. The optical communication unit is made up of a light-emittingportion for transmitting information to the image display, and alight-receiving portion for receiving command information from the imagedisplay. A change in received light quantity at the light-receivingportion is detected as an electrical signal. The electrical signal isamplified by an amplifier and output to a terminal modem. Emission ofthe light-emitting portion is controlled via a driver circuit inaccordance with a modulated signal from the terminal modem. Thesearrangements and control operations can be realized by a known method.

The optical communication unit of the image display is desirablydisposed on the upper surface of the image display housing. However, theoptical communication unit can be disposed at an arbitrary position asfar as it faces the optical communication unit of the terminal (to bedescribed below). For example, the communication unit may be disposed onthe lower surface, back surface, or front surface of the image displayhousing.

When the image display is a thin, wall-mounted monitor, its opticalcommunication unit is disposed on the upper surface of the housing, andthe optical communication unit of the terminal is disposed at a positionnear the ceiling where the optical communication unit faces the opticalcommunication unit of the image display, as shown in FIG. 46.Input/output lines to/from the image display are reduced to only a powercable and the like.

By disposing the optical communication unit of the terminal near theceiling, a complicated cable layout can be simplified without impairingthe appearance by the presence of the two optical communication units.Even a changed installation position can be dealt with by only changingthe position of the optical communication unit near the ceiling.

If the optical communication unit of the terminal is disposed above aposition where the image display is to be installed, a changedinstallation position of the image display can be easily dealt with. Theterminal can detect light from the optical communication unit of theimage display to determine that the image display at the detectedposition becomes movable. Only the optical communication unit at thisposition is biased, thereby preventing deterioration of the opticalcommunication unit.

Ninth Embodiment

In the above embodiments, one image display displays an image on onescreen. However, the present invention is not limited to this. It isalso possible to dispose a plurality of image displays close to eachother and display one image by these image displays as a whole. Theninth embodiment according to the present invention in which one imagecan be displayed by a plurality of image displays as a whole will bedescribed with reference to FIG. 47. The ninth embodiment is the same asthe above embodiments except for the following arrangement, and adetailed description thereof will be omitted.

As an example of controlling display of one image by a plurality ofimage displays as a whole, one display screen is constituted by fourimage displays in the example shown in FIG. 47. In this case, each imagedisplay may have the arrangement of the image display of the fourthembodiment shown in FIG. 34.

The terminal controls an address so as to receive only display data ofeach display screen part (1/4) of the display screen shown in FIG. 47 asvideo data for each image display.

This control enables large-screen display.

10th Embodiment

In the above embodiments, the communication timing is predetermined foreach data in communicating information between the terminal and imagedisplay, and the type of communication information can be specified atthe communication timing of the information. However, the presentinvention is not limited to this, and information may includeinformation type identification data without limiting the communicationtiming of the information. The 10th embodiment according to the presentinvention using this arrangement will be described with reference toFIG. 48. The 10th embodiment is the same as the above embodiments exceptfor the following arrangement, and a detailed description thereof willbe omitted.

In the 10th embodiment, an information transmission source adds headerdata representing the type and amount of data to be communicated to theheader of each communication information so as to allow determining thetype of communication information by the communication timing.

In the example of FIG. 48, header data is added to the header of eachinformation, as represented by hatching. The transmission source adds,to the header of video data, a header representing that data to betransmitted is video data and has a data amount of 852 dots (pixels).For audio data, the transmission source adds a header data representingthat data to be transmitted are L- and R-channel audio data.

This control eliminates wasteful idle time and allows communication of alarge amount of information. For example, necessary information can beefficiently transferred when the image display has a frame memory or thelike, or is connected to an optional device and has a large amount oftransfer data to the optional device.

Other Embodiments

The present invention can be applied to a system constituted by aplurality of devices (e.g., host computer, interface, reader, printer)or to an apparatus comprising a single device (e.g., copying machine,facsimile machine).

Further, the object of the present invention can also be achieved byproviding a storage medium storing program codes for performing theaforesaid processes to a computer system or apparatus (e.g., a personalcomputer), reading the program codes, by a CPU or MPU of the computersystem or apparatus, from the storage medium, then executing theprogram. In this case, the program codes read from the storage mediumrealize the functions according to the embodiments, and the storagemedium storing the program codes constitutes the invention. Further, thestorage medium, such as a floppy disk, a hard disk, an optical disk, amagneto-optical disk, CD-ROM, CD-R, a magnetic tape, a non-volatile typememory card, and ROM can be used for providing the program codes.

Furthermore, besides aforesaid functions according to the aboveembodiments are realized by executing the program codes which are readby a computer, the present invention includes a case where an OS(Operating System) or the like working on the computer performs a partor entire processes in accordance with designations of the program codesand realizes functions according to the above embodiments.

Furthermore, the present invention also includes a case where, after theprogram codes read from the storage medium are written in a functionexpansion card which is inserted into the computer or in a memoryprovided in a function expansion unit which is connected to thecomputer, CPU or the like contained in the function expansion card orunit performs a part or entire process in accordance with designationsof the program codes and realizes functions of the above embodiments.

When the present invention is applied to the storage medium, the storagemedium stores program codes corresponding to the aforementioned flowchart (shown in FIGS. 2, 3 and/or FIG. 4).

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the appended claims.

1. An image display control system comprising a supply source fortransmitting a signal including at least a video signal, and an imagedisplay for receiving the signal from said supply source and displayinga corresponding image, said supply source including: characteristicacquisition means for acquiring characteristic data of said imagedisplay when said supply source is powered on; determination means fordetermining a signal communication specification with said image displayon the basis of the characteristic data acquired by said characteristicacquisition means; and communication means for communicating a signalincluding the video signal with the communication specificationdetermined by said determination means, and said image displayincluding: characteristic transmission means for transmittingcharacteristic data for specifying a characteristic of said imagedisplay to said supply source; display communication means forcommunicating the signal including the video signal determined by saiddetermination means of said supply source; and connection requesttransmission means for transmitting a connection request to said supplysource, wherein said characteristic acquisition means includes detectionmeans for detecting the connection request from said image display. 2.The system according to claim 1, wherein said characteristic acquisitionmeans comprises: characteristic request means for transmitting acharacteristic data transmission request to said image display; andcharacteristic detection means for detecting the characteristic datasent back from said image display, wherein said characteristictransmission means transmits characteristic data of said image displayin correspondence with a characteristic data transmission request fromsaid supply source.
 3. The system according to claim 2, wherein saidcharacteristic request means stops transmitting the characteristic datatransmission request when no characteristic data is sent back from saidimage display even upon transmitting the characteristic datatransmission request a predetermined number of times after said supplysource is powered on.
 4. The system according to claim 2, wherein saidconnection request transmission means monitors detection of thecharacteristic data transmission request from said supply source when nocharacteristic data transmission request is sent back from said supplysource even upon transmitting the connection request a predeterminednumber of times after said image display is powered on.
 5. The systemaccording to claim 2, wherein the characteristic data transmissionrequest from said characteristic request means includes a specificationinformation transmission request of said image display, and said imagedisplay sends back specification information of said image display incorrespondence with the specification information transmission request.6. The system according to claim 2, wherein the characteristic datatransmission request from said characteristic request means includes anadjustment information transmission request of said image display, andsaid image display sends back adjustment information of said imagedisplay in correspondence with the adjustment information transmissionrequest.
 7. The system according to claim 1, wherein said determinationmeans specifies a display screen size of said image display from thecharacteristic data, obtains a video signal transmission speed incorrespondence with the specified display screen size, and determines asignal communication specification.
 8. The system according to claim 1,wherein the signal communication specification determined by saiddetermination means includes a vertical synchronization period, ahorizontal synchronization period, and a video signal transmission clockperiod for transmitting a video signal.
 9. The system according to claim1, wherein the characteristic data of said image display includes atleast any one of the number of pixels and pixel layout of a displaydevice of said image display, an emission characteristic of said displaydevice of said image display, a gray level characteristic of said imagedisplay (the number of gray levels and a gamma characteristic of saiddisplay device), the type of image display (a screen size, an aspectratio, and the type of device), a specification of an audio playbacksystem of said image display, and a displayable frame frequency of saidimage display.
 10. An image display system control method in an imagedisplay control system having a supply source for transmitting a signalincluding at least a video signal, and an image display for receivingthe signal from the supply source and displaying a corresponding image,comprising: a characteristic acquisition step of acquiringcharacteristic data of said the image display when the supply source ispowered on; a determination step of determining a signal communicationspecification with the image display on the basis of the characteristicdata acquired in said characteristic acquisition step; a communicationstep of communicating a signal including the video signal with thecommunication specification determined in said determination step, withsaid characteristic acquisition step, said determination step, and saidcommunication step being executed in the supply source; and acharacteristic transmission step of transmitting characteristic data forspecifying a characteristic of the image display to the supply source; adisplay communication step of communicating the signal including thevideo signal determined in said determination step of the supply source,with said characteristic transmission step and said displaycommunication step being executed in the image display; a connectionrequest transmission step of transmitting a connection request to thesupply source, a detection step of detecting the connection request fromthe image display.
 11. A computer program product which operates on animage display control system having a supply source for transmitting asignal including at least a video signal, and an image display forreceiving the signal from the supply source and displaying acorresponding image, comprising codes of: a characteristic acquisitionstep of acquiring characteristic data of the image display when thesupply source is powered on; a determination step of determining asignal communication specification with the image display on the basisof the characteristic data acquired in said characteristic acquisitionstep; a communication step of communicating a signal including the videosignal with the communication specification determined in saiddetermination step, with said characteristic acquisition step, saiddetermination step, and said communication step being executed in thesupply source; a characteristic transmission step of transmittingcharacteristic data for specifying a characteristic of the image displayto the supply source; a display communication step of communicating thesignal including the video signal determined in said determination stepof the supply source, with said characteristic transmission step andsaid display communication step being executed in the image display; aconnection request transmission step of transmitting a connectionrequest to the supply source, a detection step of detecting theconnection request from the image display.